July 2001
Intermediate to advanced
688 pages
16h 14m
English
The
intrinsic
exception types the CLR provides, coupled with the custom messages
shown in the previous example, will often be all you need to provide
extensive information to a catch block when an
exception is thrown. There will be times, however, when you want to
provide more extensive information or need special capabilities in
your exception. It is a trivial matter to create your own
custom exception
class; the only restriction is that
it must derive (directly or indirectly) from
System.ApplicationException. Example 11-7 illustrates the creation of a custom
exception.
Example 11-7. Creating a custom exception
namespace Programming_CSharp { using System; public class MyCustomException : System.ApplicationException { public MyCustomException(string message): base(message) { } } public class Test { public static void Main( ) { Test t = new Test( ); t.TestFunc( ); } // try to divide two numbers // handle possible exceptionsexceptions public void TestFunc( ) { try { Console.WriteLine("Open file here"); double a = 0; double b = 5; Console.WriteLine ("{0} / {1} = {2}", a, b, DoDivide(a,b)); Console.WriteLine ( "This line may or may not print"); } // most derived exception type first catch (System.DivideByZeroException e) { Console.WriteLine( "\nDivideByZeroException! Msg: {0}", e.Message); Console.WriteLine( "\nHelpLink: {0}\n", e.HelpLink); } catch (MyCustomException e) { Console.WriteLine( "\nMyCustomException! Msg: {0}", e.Message); Console.WriteLine( "\nHelpLink: ...